Chemical to mechanical energy converter

ABSTRACT

A contractile polymer member is immersed in a denaturing medium. Means is provided to alternately increase and decrease the concentration of that portion of the medium which is in the neighborhood of the contractile polymer member. This causes the member to alternately contract and expand. The member is connected to a ratchet driven shaft for translating the member&#39;&#39;s reciprocal contractile movement into rotary movement.

United States Patent Soto et al.

[451 Sept. 25, 1973 CHEMICAL TO MECHANICAL ENERGY CONVERTER Ricardo J. Soto, Milwaukee; Robert T. Balmer, Shorewood, both of Wis.

Aug. 3, 1972 Inventors:

Filed:

Appl. No.:

US. Cl 74/128, 60/23, 264/202,

264/360 Int. Cl. Fl6h 27/02 Field of Search 60/23; 74/128 References Cited UNITED STATES PATENTS 7/1900 Dodds 60/23 7/1933 Ruben 3/1934 Scheibell 60/23 3,587,227 6/ I 971 Wiengarten 60/23 Primary Examiner-Charles J. Myhre Assistant ExaminerWesley S. Ratliff, Jr. Attorney-Arthur L. Morsell, Jr.

[57] ABSTRACT 19 Claims, 12 Drawing Figures CHEMICAL TO MECHANICAL ENERGY CONVERTER BACKGROUND OF THE INVENTION In recent years, an intolerably high level of air pollution has been generated in large metropolitan areas by internal combustion engines in automobiles, trucks, construction equipment, and the like. An earnest search has, therefore, been conducted by many workers in the field to find ways of decreasing the pollution content in the exhaust gases of internal combustion engines and also to develop alternate mechanical power sources which are inherently non-polluting in nature.

In the search for non-polluting mechanical power sources, one basic principle that has been largely overlooked is the principle that underlies the action of animal muscles, i.e., the direct conversion of chemical energy into mechanical energy by means of contractile fibers. It has been known in the past that contractile materials exist which can be caused to contract by contact with a denaturing medium and which can be subsequently expanded by washing away the denaturing medium. A laboratory scale turbie has been devised in the past for utilizing the contractions and expansions of such contractile materials to turn a shaft. In this turbine, an endless loop of contractile polymer fiber is wound around two tapered, rotatable spindles which are immersed in a denaturant solution. When the fiber contacts the denaturant solution, it contracts and causes the spindles to rotate slowly and move the fiber therealong. After leaving the spindles, the fiber moves through a separate tank of fresh water to expand back to its initial state so that it can be utilized on the next cycle to turn the spindle again. In this manner, a relatively slow continuous rotation of the spindles is achieved.

But, although the above-described turbine was useful for laboratory demonstration purposes, it was limited to such purposes due to the fact that the contractile material had to be arranged in the form of a relatively long endless loop, and this form cannot be enlarged very far to permit multiplication of the output power. Accordingly, the use of contractile fibers as a mechanical power source has been limited to laboratory demonstrations in the past. In accordance with this invention, however, novel apparatus has been devised in which contractile fibers can be utilized in large scale applications as a mechanical power source. The apparatus of this invention can be used to drive water pumps, air compressors, electrical generators, automobiles, and the like. In smaller applications, it can be used as a pH meter, a servo control mechanism, a saline-acid detector, and the like. In all of these applications, the apparatus is not only nearly pollution free but also silent in operation.

SUMMARY OF THE INVENTION A contractile polymer member is immersed in a denaturing medium. Means is provided to alternately increase and decrease the concentration of that portion ofthe medium which is in the neighborhood of the contractile polymer member. In one embodiment of the invention, this is done by establishing a pulsating electric potential gradient through the medium to alternately transport ions away from the contractile polymer member and allow them to return under the impetus of a concentration gradient. When the concentration of the medium increases in the neighborhood of the contractile polymer member, it will contract, and when the concentration of the medium decreases, the member will expand. Therefore, the pulsating electric potential gradient causes alternating contractions and expansions of the contractile polymer member. The same effect is gained in other embodiments of the invention by other methods of forced diffusion such as pulsating fluid pressure gradients and temperature gradients which can be made more effective via connection with ion selective and permselective membranes. One end of the contractile polymer member is attached to a supporting structure and the other end is attached to a mechanical output mechanism for utilizing the alternate contractions and expansions of the member. In one embodiment of the invention, the output mechanism is a ratchet driven rotary shaft. I

One object of this invention is to provide novel apparatus for direct conversion of chemical energy into mechanical energy.

Another object of this invention is to provide a novel mechanical drive mechanism which is powered by a contractile polymer member.

A further object of this invention is to provide a novel means for alternately increasing and decreasing the concentration of a denaturing medium in the neighborhood of a contractile polymer member immersed therein.

An additional object of this invention is to provide a novel means for causing a contractile polymer member to alternately contract and expand.

Another object of this invention is to provide a novel source of reciprocating mechanical motion.

A further object of this invention is to provide a mechanical power source in which a reciprocating mechanical movement is produced by alternately increasing and decreasing the concentration of that portion of a denaturing medium which is in contact with a contractile polymer member immersed therein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation view of one illustrative embodiment of the invention;

FIG. 2 is a plan view of the embodiment shown in FIG. 1;

FIG. 3 is an enlarged detail view of the ratchet mechanism and associated parts for the embodiment shown in FIGS. 1 and 2;

FIG. 4 is a block diagram of the electrical circuit for creating a pulsating potential gradient in the embodiment shown in FIGS. 1 to 3;

FIG. 5 is a diagrammatic representation of a second embodiment of the invention;

FIG. 6 is a diagrammatic representation of a third embodiment of the invention;

FIG. 7 is a diagrammatic representation of a fourth embodiment of the invention;

FIG. 8 is a top view of one illustrative electrode configuration for use in connection with this invention;

FIG. 9 is a top view of a second electrode configuration for use in connection with this invention;

FIG. 10 is a top view of a third electrode configuration for use in connection with this invention;

FIG. 11 is a top view of a fourth electrode configuration for use in connection with this invention; and

FIG. 12 is a graph of force vs. molality for a typical contractile polymer immersed in a typical denaturing medium.

DETAILED DESCRIPTION OF THE INVENTION This invention is based upon the contraction and expansion of a contractile polymer member which contracts when it is immersed in a denaturing medium and expands when the denaturing medium is washed away. The denaturing medium can be either a gas or a liquid denaturant medium. In the past, such contractions and expansions were achieved by first running the contractile polymer member through a tank containing a denaturant solution and then running it through a second tank containing fresh water. But the requirement for running the contractile polymer member through two different tanks was a limiting factor which limited the application of contractile polymer members to laboratory scale demonstrations. In accordance with this invention, however, contraction and expansion of a contractile polymer member is achieved in a single container of denaturing medium by alternately increasing and decreasing the concentration of the denaturing medium in the neighborhood of the contractile polymer member. This allows the contractile polymer member to be made in physical configuration which can be easily scaled up for large scale applications or down for small scale applications.

One example of a suitable contractile polymer which can be used in connection with this invention is reconstituted collagen fiber which has been cross-linked with formaldehyde. Reconstituted collagen fiber is a type of protein which is derived from animal tissues and is used primarily as a suture. The reconstituted collagen fiber can be cross-linked with formaldehyde by dipping it in a 0.5 percent or greater aqueous formaldehyde solution and allowing the formaldehyde solution to dry on the fiber for 24 hours. The cross-linking with formaldehyde is necessary to hold the collagen fiber together since it would otherwise tend to disintegrate when immersed in a liquid denaturing medium.

Examples of suitable denaturants to be used in connection with this invention are aqueous solutions of Lithium Bromide, Potassium Thyocyanate, Nitric Acid, Hydrochloric Acid, and Zinc Chloride. A graph showing the normalized reconstituted collagen fiber immersed in these denaturant solutions is shown in FIG. 12. The curve A is plotted as the relationship between F/F and M/M* where F force for a given denaturant; F,,, maximum force for a given denaturant; M molality; and M* 55.55/N where N is the hydration number of the denaturant. Although there is some variation in curves for the individual denaturants, most of them follow the curve A quite closely, at least between the molality values B and C, which define the-M/M* range of 0.5 to 1.0. This is the preferable range within which the concentration of the denaturants are varied to produce the alternate contractions and expansions of the collagen fiber.

For further information regarding the behavior of cross-linked reconstituted collagen fibers in different denaturant solutions, the reader is referred to the thesis entitled Contraction-Relaxation Studies of Collagen Fibers," by Ricardo Javier Soto, which was submitted to the University of Wisconsin to Milwaukee in December, 1971, and which is available from the library upon request. This thesis covers the effect of the following denaturants, all of which are usable in connection with this invention: ZnCl CuCl FeCI CaCl MgCl NaI; LiBr; LiCl; HI; HCI; SnCI KCNS; KI: NaCNS; HBr; and HF.

As noted above, this invention involves inducing alternate contractions and expansions in a contractile polymer member such as a length of cross-linked reconstituted collagen fiber by alternately increasing and decreasing the concentration of a denaturing medium in the neighborhood of the fiber. One means for accomplishing this result is to establish a pulsating potential gradient through the denaturing medium to alternately transport ions away from the contractile polymer member and allow them to return under the impetus of a concentration gradient. When the concentration of the solution increases in the neighborhood of the contractile polymer member, it will contract, and when the concentration of the solution decreases, the member will expand. Therefore, the pulsating electric potential gradient causes alternating contractions and expansions of the contractile polymer member.

FIGS. 1, 2, 3, and 4 show a laboratory scale selfpropelled vehicle that utilizes the above-described pulsating electric potential gradient. Referring to FIGS. 1 through 4, this embodiment includes a bottom frame member 10 having two rear wheels 12 journalled thereto via an axle 14. The wheels 12 are rigidly attached to axle l4, and the axle 14 is journalled to bottom frame member 10 by passing through an opening therein. A front wheel 16 is journalled via an axle 18 to a yoke 20 which is pivoted to bottom frame member 10 by a bolt 22 which passes through openings in the yoke 20 and the bottom frame member 10. Two upright frame members 24 and 26 are rigidly attached to bottom frame member 10 and project upwardly therefrom. The upright frame members 24 and 26 are joined together at their top by a top frame member 28.

Two metallic support blocks 30 and 32, both of which have transverse central openings therein, are attached to the upper surface of top frame member 28. The support block 30 has a shaft 34 journalled through the central opening therein. A large pulley wheel 36 and a small gear 38 are rigidly attached to the shaft 34. The large pulley wheel 36 has a grooved rim for receiving a resilient drive belt 40 which extends around a small grooved pulley wheel 42 that is rigidly attached to rear axle 14 for driving the same. When the small gear 38 is rotated, the rear axle 14 is driven by the two pulley wheels 36 and 42 via the resilient drive belt 40 extending thereinbetween.

The support block 32 has a shaft 44 journalled through the central opening therein. A relatively large gear 46 which meshes with small gear 38 is rigidly attached to shaft 44, and a ratchet drive mechanism 48 is also rigidly attached to shaft 44. When a reciprocating motion is applied to the ratchet drive mechanism 48, it causes the gear 46 to rotate, which drives gear 38, pulley wheels 36 and 42, and axle 14. The reciprocating drive motion for ratchet drive mechanism 48 is derived from a group of contractile polymer fibers which are alternately contracted and expanded as will be described below.

A small tank 50 which is made of suitable water proof and corrosion proof material is attached to upright frame member 26 for containing a denaturant solution which may be one of the denaturants specified above or any other denaturant that will cause cross-linked reconstituted collagen fibers to contract. The molality of the denaturant solution is preferably in the range of 0.5 to 1.0 for the ratio M/M* where M molality and M* 55.55/N where N is the hydration number of the denaturant. A fixed pin 52 passes through the sides of tank 50 near the lower end thereof and is rigidly secured thereto. A length of cross-linked reconstituted collagen fiber 54 or some other suitable contractile polymer is repeatedly wound around the pin 52 and also around a loose pin 56 which is attached to a rod, 58. The rod 58 is attached to a fitting 60 which is attached to a horizontal arm 62 and a spring 64. The horizontal arm 62 is attached to ratchet drive mechanism 48 and the other end of spring 64 is attached to an arm 66 which is attached to support block 32.

As shown in FIG. 3, the ratchet drive mechanism 48 includes a housing 68, a ratchet wheel 70, and a pawl 72. The ratchet wheel 70 is rigidly attached to shaft 44 and the pawl 72 is pivotally attached to the housing 68. As the housing 68 is rotated counterclockwise by arm 62, the pawl 72 engages the teeth of ratchet wheel 70 and causes it to rotate in the counterclockwise direction. This causes shaft 44 and gear 46 to rotate in the counterclockwise direction. When the housing 68 is rotated in the clockwise direction, the pawl 72 rides up over the teeth of ratchet wheel 70 without causing any rotation.

Two metallic electrodes 74 and 76 are mounted to opposing inner walls of tank 50. Electrodes 74 and 76 extend for the length of the collagen fiber 54 and are preferably reversible electrodes. There are four types of reversible electrodes, any one of which can be used in connection with this invention: (1) a metal in contact with a solution of its own ions; (2) a metal, a sparingly soluble salt of the metal, and a solution of a soluble salt ofthe same anion; (3) a metal, one ofits insoluble salts, an insoluble salt of the same anion, and'a solu-' tion of a soluble salt having the same cation as the latter salt; and (4) an unattackable metal such as platinum or gold immersed in a solution containing ions in two valence states.

Electrodes 74 and 76 are connected by means of electric terminals 78 and 80 and appropriate conductors to a pulsating electric potential source 82. FIG. 4 shows a block diagram of pulsating potential source 82. It contains a free running multi-vibrator 84 having a manual frequency adjustment and a power amplifier 86. This circuit is powered by batteries which are not shown in the drawings. This circuit establishes a pulsating potential between electrodes 74 and 76, which establishes a pulsating potential gradient across the tank 50. This pulsating potential gradient alternately increases and decreases the concentration of the denaturant solution in the neighborhood of collagen fibers 54 and thus causes alternate contraction and expansion of the same. These expansions and contractions provide the reciprocal movement of arm 62 which is necessary to drive ratchet 48.

FIGS. 5, 6, and 7 show three additional methods of causing alternate contractions and expansions of contractile polymer members immersed in denaturing mediums. In FIG. 5, a tank 88 is filled with a denaturing medium 90 and has two contractile polymer members 92 attached between the bottom of tank 88 and a movable rod 94. The contractile polymer members 92 are flanked by ion selective membranes 96 and 98 which divide tank 88 into cells. The membranes 96 block passage of positive ions while the membrane 98 blocks the passage of negative ions. A pair of electrodes 100 are mounted on opposing sides of the tank 88 and are coupled to the output of a pulsating voltage source 102.

In the device of FIG. 5, the denaturing medium 90, the contractile polymer members 92, and the electrodes 100 may be the same as described in the previous embodiment. The positive ion selective membranes 96 may be protamine collodion and the negative ion selective membrane 98 may be linear polystyrene sulphonic acid and polyvinyl alcohol heat treated. In operation, this embodiment is similar to the previously described embodiment except that the membranes 96 and 98 limit the movement of the denaturing ions toward the electrodes 100. The end result is the same, however, i.e., the pulsating electric potential gradient causes an alternating increase and decrease in the concentration of the denaturing medium in the neighborhood of the contractile polymer membranes 92. This causes the contractile polymer members 92 to alternately contract and expand.

In FIG. 6, a completely closed tank 104 is filled with a denaturant solution 106. Tank 104 is divided into three compartments by membranes 108 which may be polymethacrylic acid or the like. Contractile polymer members 110 are immersed in the three compartments and connected to a movable rod 112. This embodiment works by reverse osmosis in response to a pressure gradient. Alternating pressures are applied at A, B, and C by any suitable means to provide alternating pressure gradients across the membranes 108. This causes the solvent to pass through the membranes 108 from the high pressure side to the low pressure side but blocks the flow of solute. As a result, the concentration of the solution is increased on the high pressure side of the membrane and decreased on the low pressure side. By alternating the high pressure side of the membranes, the concentration of the solution'in each of the three compartments can be alternately raised and lowered to cause alternate contractions and expansions of the contractile polymer members 110.

In FIG. 7, a tank 114 is filled with a denaturant solution 116 and is divided into three compartments by membranes 118 which may be copper ferrocyanide or cellophane. A pulsating temperature gradient is set up across the membranes 118 by electric heaters 120 which are immersed in the solution 116 and are coupled to a pulsating voltage source 122. A contractile polymer member 124 is immersed in the denaturant solution 116 in the central chamber of tank 114.

The temperature gradient causes movement of the solvent through the membrane 118 from the high temperature side to the low temperature side. This increases the concentration of the solution on the high temperature side of membrane 118 and decreases the concentration of the solution on the low temperature side. When the temperature gradient drops, the solute moves through the membranes 118 in the same direction under the impetus of a concentration gradient. This causes the concentration of the solution 116 to alternately increase and decrease in the neighborhood of the contractile polymer member 124 and causes the latter to alternately contract and expand.

FIGS. 8,9, 10, and 11 show top views of different electrode configurations that can be used in connection with this invention. In FIG. 8, a rectangular tank 126 has a contractile polymer member 128 therewithin.

Two flat, rectangular metal electrodes 130 are mounted on opposing interior surfaces of the tank 126 on opposite sides of the contractile polymer member 128. Two electrical terminals 132 are attached to the electrodes 130 for transmitting electric potentials thereto.

In FIG. 9, two hollow semi-cylindrical electrodes 134 are joined to insulating strips 136 to make a hollow cylindrical electrode configuration that surrounds a cylindrical contractile polymer member 138. Two electrical terminals 140 are attached to the electrodes 134 for transmitting electric potentials thereto.

In FIG. 10, a hollow cylindrical electrode 142 surrounds a hollow cylindrical contractile polymer member 144. A small cylindrically shaped electrode 146 is positioned within hollow cylindrical member 144. An electric terminal 148 is attached to electrode 142 for transmitting electric potentials thereto. Another terminal which is not shown in the drawing transmits electric potentials to electrode 146.

H6. 11 shows a hollow cylindrical electrode 150 which surrounds a cylindrical contractile polymer member 152 that has a group of longitudinal openings therein through which a plurality of cylindrical electrodes 154 project. An electric terminal 156 is attached to electrode 150 for transmitting electric potentials thereto. Another electric terminal which is not shown in the drawing transmits electric potentials to the plurality of cylindrical electrodes 154.

From the foregoing description it will be clear that this invention provides a novel apparatus for converting chemical energy into mechanical energy. And although this invention has been described in connection with several illustrative examples thereof, it should be understood that the invention is not limited to the disclosed examples since many modifications can be made in the disclosed structure without changing its fundamental principles of operation. For example, although a laboratory scale self-propelled vehicle has been disclosed herein, the basic power source for the vehicle and the transmission mechanism therefor can be quite easily scaled up and adapted for full size vehicles. Also, the disclosed devices can be modified to be used as a power source for pumps, compressors, and the like. These and other modifications of the disclosed structure will be apparent to those skilled in the art and this invention includes all modifications falling within the scope of the following claims.

What we claim is:

1. A chemical to mechanical energy converter comprising a contractile polymer member, a denaturing medium of the type that will cause contraction of said contractile polymer member when placed in contact with the same, means for maintaining said denaturing medium in contact with said contractile polymer member, means for alternately increasing and decreasing the concentration of that portion of said medium which is in the neighborhood of said contractile polymer member to alternately contract and expand the latter, mechanical output means, and means connected between said contractile polymer member and said output means for transmitting the alternate contractions and expansions of said contractile polymer member to said output means.

2. The combination defined in claim 1 wherein said means for alternately increasing and decreasing the concentration of a portion of said medium comprises means for generating a pulsating electric potential gradient through said medium in the neighborhood of said contractile polymer fiber.

3. The combination defined in claim 1 wherein said contractile polymer member is immersed in said medium and wherein said means for alternately increasing and decreasing the concentration of a portion of said medium comprises a pair of electrodes immersed in said medium on opposite sides of said contractile polymer member and a pulsating voltage source coupled to said electrodes for generating a pulsating electric potential gradient through said medium in the neighborhood of said contractile polymer fiber.

4. The combination defined in claim 1 and further comprising a tank for containing said medium, a plurality of ion selective membranes immersed in said tank and positioned to divide said tank into compartments, said contractile polymer member being immersed in said medium in one of said compartments, a pair of electrodes immersed in said medium on opposite sides of said tank, and a pulsating voltage source coupled to said electrodes for generatinga pulsating electric potential gradient through said medium in the neighborhood of said contractile polymer member.

5. The combination defined in claim 4 wherein said ion selective membranes comprise a first type of membrane which blocks the passage of positive ions and a second type of membrane which blocks the passage of negative ions, said first and second types of membrane being positioned alternately across said tank.

6. The combination defined in claim 5 wherein said first type of membrane is made of protamine collodion and said second type of membrane is made of linear polystyrene sulphonic acid and polyvinyl alcohol heat treated.

7. The combination defined in claim 1 and further comprising a tank for containing said medium, a plurality of membranes immersed in said tank and positioned to divide said tank into compartments, said contractile polymer member being immersed in said medium in one of said compartments, and means for generating an alternating pressure gradient across said membranes defining the compartment that contains said contractile polymer member, thereby alternately increasing and decreasing the concentration of said medium in the compartment that contains said contractile polymer member.

8. The combination defined in claim 7 wherein said membranes are made of polymethacrylic acid.

9. The combination defined in claim 1 and further comprising a tank for containing said medium, a plurality of membranes immersed in said tank and positioned to divide said tank into compartments, said contractile polymer member being immersed in said medium in one of said compartments, and means for generating a pulsating temperature gradient across said membranes defining the compartment that contains said contractile polymer member, thereby alternately increasing and decreasing the concentration of said medium in the compartment that contains said contractile polymer member.

10. The combination defined in claim 9 in which said means for generating a pulsating temperature gradient across said membranes comprises a pair of electric heaters immersed in said medium adjacent to said membranes and a pulsating voltage source coupled to said electric heaters for energizing the same.

11. The combination defined in claim wherein said membrane is made of copper ferrocyanide.

12. The combination defined in claim 1 wherein said denaturing medium is an aqueous solution of one of the following group of denaturants: ZnCl CuCl FeCl CaCl MgCl Nal; LiBr; LiCl; HI; HCl; SnCl; KCNS; Kl; NaCNS; HBr; and l-lf.

13. The combination defined in claim 12 wherein the concentration of said aqueous solution is within the range M/M* 0.5 and M/M* 1.0 where M molality and M* 55.55/N where N is the hydration member of said denaturant.

14. The combination defined in claim 12 wherein said contractile polymer member comprises reconstituted collagen which is cross-linked with formaldehyde.

15. The combination defined in claim 14 wherein said contractile polymer member is cross-linked with formaldehyde by being dipped in an aqueous formaldehyde solution of at least 0.5 percent and then being allowed to dry for 24 hours.

16. The combination defined in claim 3 wherein each of said electrodes are shaped in the form of hollow, semi-cylindrical shells, said electrodes being joined together with strips of insulating material separating the edges thereof to form a hollow cylindrical electrode assembly.

17. The combination defined in claim 3 wherein said contractile polymer member is shaped in the form of a hollow cylinder, one of said electrodesbeing shaped in the form of a hollow cylinder whose inside diameter is larger than the outside diameter of said contractile polymer member and being positioned around the exterior of said contractile polymer member, and the other electrode being shaped in the form of a cylinder whose outside diameter is smaller than the inside diameter of said contractile polymer member and being positioned within the hollow interior of said contractile polymer member.

18. The combination defined in claim 3 wherein said contractile polymer member is shaped in the form of a cylinder having a plurality of longitudinal openings therein, and wherein one of said electrodes is shaped in the form of a plurality of cylinders each of whose outside diameter is smaller than the inside diameter of said longitudinal openings in said polymer member, each of said plurality of cylinders being positioned within a corresponding longitudinal opening in said polymer memher, and the other electrode being shaped in the form of a hollow cylinder whose inside diameter is larger than the outside diameter of said contractile polymer member and being positioned around the exterior of said contractile polymer member.

19. The combination defined in claim 1 wherein said mechanical output means includes a shaft, and wherein said means connected between said contractile polymer member and said output means includes a ratchet mechanism for translating the reciprocal contractile movement of said contractile polymer member into rotation of said shaft.

UMIED STATES PATENT otmcr, QE'RTEFHQATE 0F CORRECTION Ptent 5.760.646 Dated September 25. 1975 Inventofl Ricardo J. Soto and Robert T. Balmer I It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown' below:

Column 1,: line 25, change "turbie" to turbine Oolumn 3, line +6, between the words 7'normalized" and V "reconstituted" insert the words relationship of force vs. molality 'for a cross-linked Column 9, line 11, change member to number Signedehd Sealed this 25th day of December1973.

Attest': v

EDWARD M.PLETCHER,JR. I RENE. D. TEGTMEYER Attesting Officer 7 a Acting Commissioner of Patents FORM PO-1OS0 (10-69) USCOMM-DC 60376-P69 I U.S. GOVERNMENT PRINTING OFFICE "I. O- 3ii334 

2. The combination defined in claim 1 wherein said means for alternately increasing and decreasing the concentration of a portion of said medium comprises means for generating a pulsating electric potential gradient through said medium in the neighborhood of said contractile polymer fiber.
 3. The combination defined in claim 1 wherein said contractile polymer member is immersed in said medium and wherein said means for alternately increasing and decreasing the concentration of a portion of said medium comprises a pair of electrodes immersed in said medium on opposite sides of said contractile polymer member and a pulsating voltage source coupled to said electrodes for generating a pulsating electric potential gradient through said medium in the neighborhood of said contractile polymer fiber.
 4. The combination defined in claim 1 and further comprising a tank for containing said medium, a plurality of ion selective membranes immersed in said tank and positioned to divide said tank into compartments, said contractile polymer member being immersed in said medium in one of said compartments, a pair of electrodes immersed in said medium on opposite sides of said tank, and a pulsating voltage source coupled to said electrodes for generating a pulsating electric potential gradient through said medium in the neighborhood of said contractile polymer member.
 5. The combination defined in claim 4 wherein said ion selective membranes comprise a first type of membrane which blocks the passage of positive ions and a second type of membrane which blocks the passage of negative ions, said first and second types of membrane being positioned alternately across said tank.
 6. The combination defined in claim 5 wherein said first type of membrane is made of protamine collodion and said second type of membrane is made of linear polystyrene sulphonic acid and polyvinyl alcohol heat treated.
 7. The combination defined in claim 1 and further comprising a tank for containing said medium, a plurality of membranes immersed in said tank and positioned to divide said tank into compartments, said contractile polymer member being immersed in said medium in one of said compartments, and means for generating an alternating pressure gradient across said membranes defining the compartment that contains said contractile polymer member, thereby alternately increasing and decreasing the concentration of said medium in the compartment that contains said contractile polymer member.
 8. The combination defined in claim 7 wherein said membranes are made of polymethacrylic acid.
 9. The combination defined in claim 1 and further comprising a tank for containing said medium, a plurality of membranes immersed in said tank and positioned to divide said tank into compartments, said contractile polymer member being immersed in said medium in one of said compartments, and means for generating a pulsating temperature gradient across said membranes defining the compartment that contains said contractile polymer member, thereby alternately increasing and decreasing the concentration of said medium in the compartment that contains said contractile polymer member.
 10. The combination defined in claim 9 in which said means for generating a pulsating temPerature gradient across said membranes comprises a pair of electric heaters immersed in said medium adjacent to said membranes and a pulsating voltage source coupled to said electric heaters for energizing the same.
 11. The combination defined in claim 10 wherein said membrane is made of copper ferrocyanide.
 12. The combination defined in claim 1 wherein said denaturing medium is an aqueous solution of one of the following group of denaturants: ZnCl2; CuCl2; FeCl3; CaCl2; MgCl2; NaI; LiBr; LiCl; HI; HCl; SnCl; KCNS; KI; NaCNS; HBr; and Hf.
 13. The combination defined in claim 12 wherein the concentration of said aqueous solution is within the range M/M* 0.5 and M/M* 1.0 where M molality and M* 55.55/N where N is the hydration member of said denaturant.
 14. The combination defined in claim 12 wherein said contractile polymer member comprises reconstituted collagen which is cross-linked with formaldehyde.
 15. The combination defined in claim 14 wherein said contractile polymer member is cross-linked with formaldehyde by being dipped in an aqueous formaldehyde solution of at least 0.5 percent and then being allowed to dry for 24 hours.
 16. The combination defined in claim 3 wherein each of said electrodes are shaped in the form of hollow, semi-cylindrical shells, said electrodes being joined together with strips of insulating material separating the edges thereof to form a hollow cylindrical electrode assembly.
 17. The combination defined in claim 3 wherein said contractile polymer member is shaped in the form of a hollow cylinder, one of said electrodes being shaped in the form of a hollow cylinder whose inside diameter is larger than the outside diameter of said contractile polymer member and being positioned around the exterior of said contractile polymer member, and the other electrode being shaped in the form of a cylinder whose outside diameter is smaller than the inside diameter of said contractile polymer member and being positioned within the hollow interior of said contractile polymer member.
 18. The combination defined in claim 3 wherein said contractile polymer member is shaped in the form of a cylinder having a plurality of longitudinal openings therein, and wherein one of said electrodes is shaped in the form of a plurality of cylinders each of whose outside diameter is smaller than the inside diameter of said longitudinal openings in said polymer member, each of said plurality of cylinders being positioned within a corresponding longitudinal opening in said polymer member, and the other electrode being shaped in the form of a hollow cylinder whose inside diameter is larger than the outside diameter of said contractile polymer member and being positioned around the exterior of said contractile polymer member.
 19. The combination defined in claim 1 wherein said mechanical output means includes a shaft, and wherein said means connected between said contractile polymer member and said output means includes a ratchet mechanism for translating the reciprocal contractile movement of said contractile polymer member into rotation of said shaft. 